First, we need to look at the structure or a hypothesis and boil it down to its component parts, A scientific hypothesis simply consists of 2 parts. Therefore, if we use a 2-step template to help students write a scientific hypothesis, students may find this more helpful. We go through our 2-step hypothesis and applicable examples below. Handouts are available at the end of the post.

What is a scientific hypothesis?

Basically, a scientific hypothesis is a testable explanation for a scientific phenomena or question. Let’s break that down.

First, a scientific hypothesis is a scientific explanation. A statement that makes clear the causes or reasons for a scientific phenomena or question. For example, we could ask, “how do musicians sell more records?”  And, our hypothesis could be “Record sales depend on the amount of impressions or views the record receives online.” So, is this a good scientific hypothesis? It’s close, but it’s still incomplete.

Besides being an explanation, a scientific hypothesis must also be testable. In other words, scientists can observe or measure changes when they adjust or manipulate parts of the hypothesis in an experiment. The testable part of a scientific hypothesis typically comes in the form of an “if, then” statement. For example, to make the above hypothesis about musical record sales more complete, we can add the following: “If the number of Youtube views for a record increases, then the number of sales for the record will increase.”

The 2-step approach to hypothesis writing

Perhaps a straightforward way to teach hypothesis writing is to take a 2-step approach and to make a hypothesis at least 2 sentences long.

Note: there is no accepted length requirement to a hypothesis, although many students may get the wrong impression that a hypothesis is supposed to be 1 sentence in length.

Also note: before students begin to write a hypothesis, they must start with a question, which either they receive or come up with. If a phenomenon or experimental evidence is given instead, then this can be turned into a question by asking “why does that happen? Or “how does <the phenomenon> work?”. With question in hand, students can start the 2-step hypothesis writing process.

How to do a 2-step hypothesis

STEP 1: Come up with a specific reason or reasons that explain the phenomena or question. Consider using the following template to start your hypothesis:

The <phenomenon, topic> (is due to, is caused by, depends on) <specific reason>

Make sure students provide specific details. For example, saying “Record sales depend on an artist’s popularity” isn’t specific enough.

To make a stronger statement, define what type of popularity. For example, “Record sales depend on an artist’s popularity – specifically, the number of online followers the artist has before the release of the album”. This is a much stronger statement as it defines what type of popularity (ie. Online, social media) and when (ie. Before the release of an album).

STEP 2: Write a testable statement. In other words, provide a way in which the hypothesis can be tested.. Consider using an “If, then” statement and structure the statement like this:

“If <independent/manipulated> variable <increases/decreases>, then <dependent/respondent> variable <increases/decreases>”

Remember, a independent or manipulated variable is something a scientist or researcher has the power to directly change. The dependent or respondent variable is the something that responds to the changes of the independent variable. In the case for our hypothesis above, online followers is the independent variable and record sales is the dependent variable.

Therefore, we can write the testable statement “If the number of online followers an artist has increases, then the artist’s record sales increases.” This is a fairly straightforward statement that is easily testable. That is, track an artist’s online followers and see if it correlates with an increase in record sales.

Aside: There is no one “right” hypothesis

Lastly, there can be many hypotheses that explain the same phenomena. Students do not need to feel as though they need to get the “right one”. For example, for our question, “How do musicians sell more records?”, there can be multiple hypotheses – all of which can be credible:

“Record sales depend on the amount of radio play the record receives. If the radio play for a record increases, then the number of sales for that record increases.”

“Record sales depend an artist’s activity on social media platforms. If the number of Facebook Live, SnapChat, and Reddit AMA events hosted by the artist increases, then the artist’s record sales increase.”

“Record sales depend on early reviews by ‘influencers’. If number of early reviews by influencers increases, then the artist’s record sales increase.”

Wrap Up

Part of teaching science is teaching scientific literacy. Experimental design, identifying variables, hypothesis writing – are all part of that scientific literacy. To help students grasp science literacy quicker, it’s important to provide templates and standard customs, both of which teachers may already know bit take for granted. Click the link below to download our handouts. Thanks for your interest! Also, if you find this resource helpful, please share this with your colleagues.

Until next time, keep it REAL!

Resources

Handout(s): 35 – 2 Step Hypothesis Writing

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In this resource, we discuss the language and conventions we use in presenting science experiments and results. As science teachers, we don’t notice these conventions because we’re so used to them. They’re like little tips science teachers have grown accustomed to. But, these conventions help us to decipher important information like independent and dependent variables. And, by teaching students these same conventions, they’ll be being able to extract the same information regardless of what data is given. We have a cheat sheet available for download at the end of this post.

What are Independent and Dependent variables?

An independent variable is the condition or factor a scientist changes during the experiment.

A dependent variable is the condition or factor a scientist measures in order to study the effects of the changes made to the independent variable.

Both independent and dependent variables are conditions the scientist measures and conditions in an experiment that change. But, independent variables are usually set or altered by the researcher to test an idea while dependent variables are measured during or after the experiment. In other words, a researcher can control or preset independent variables, while a researcher cannot preset a dependent variable.

Thus, one way to identify independent and dependent variables is to refer to the experimental procedure. Ask, what is the researcher changing between trials or is planning to alter during their research? This is the independent variable. Also, ask, what change is the researcher trying to measure to determine the effectiveness of their experiment? This is the dependent variable.

How else to identify independent and dependent variables

In the title

A common structure to the title of a science experiment goes like this: “The effect of x on y”.

For example, “The effect of climate change on the migratory patterns of ducks”.

More specifically, the common structure of the title is one that goes like this: “The effect of <independent variable> on <dependent variable>.”

Therefore, in our title example above, the independent variable in the experiment is climate change (and likely aspects of climate change like temperature). And, the dependent variable for the same experiment is migratory patterns of ducks.

In the graph

The structure of a graph – be it a bar graph or linear graph – will have one variable plot along the x-axis and another on the y-axis.

For example, the following graph is a climatograph for a specific biome.

The value plot along the x-axis – months of the year – is the independent variable. The value – or, in this case, values – plot on the y-axis are the dependent variables. There are 2 for this graph: temperature and precipitation.

In the hypothesis

The structure of the typical testable, predictive hypothesis is an “If…then…” statement.

For example, “If the temperature of the liquid increases, then the time it takes salt to dissolve decreases.”

More specifically, the structure of the typical, testable hypothesis is a statement that goes like this: “If <independent variable> increases/decreases, then <dependent variable> increases/decreases.”

Therefore, in our hypothesis example above, the independent variable for the experiment is temperature of the liquid and the dependent variable is the time it takes salt to dissolve.

Wrap Up

Our job as science teachers is to teach science literacy. We teach not just the content but the language of how that content is presented. By teaching the structure of that language, the conventions that scientists use, we make science easier (and, hopefully, quicker) for students to grasp. The conventions we wrote about in this resource represent just a few. There are many more we can present to our students. Click on the link below to download our handouts to this post.

Until next time, keep it REAL.

Resources

Handout(s): 34 – 3 Tips to Identify IV and DV

Our resources are free. We aren’t collecting emails for our resources. However, it would help us out if you liked us on our Facebook page and subscribed to our Youtube Channel. Thanks!

The problem with Typical Questions

Typical practice questions are fine if you want students to be able to pick between two variables to determine which one is dependent or independent. Unfortunately, typical practice questions are bland and limited in scope. What if you want students to think outside the box? What if you want students to flex their creative muscles in designing their own experiments? This invariably starts with identifying a unique independent and dependent variable that doesn’t come from a statement off a worksheet.

In this resource, we propose using open-ended experimental design statements to have students practice identifying independent and dependent variables in fun and relevant situations. Also, we provide a worksheet of our own with 10 statements you can use in your classroom. The worksheet is available for download at the end of this post.

Thought Experiments for Variable Practice

A simple observation of independent and dependent variable practice worksheets is that the statements are usually all thought experiments. So, why not make the thought experiments fun and relevant? Also, why not make answers open ended as opposed to a choice between two items included in the design question. Therefore, instead of asking for the effect fertilizer use (independent variable) has on plant growth (dependent variable), why not discuss the multiple variables that can grow the social media presence of a small business?

The Case for Inquiry Questions

In our practice activity, we provide inquiry questions and ask for students to identify some examples of independent or dependent variables in each case. However, a twist we add is that we fix one variable and then ask for multiple examples of the other. For example, consider the inquiry question, “How do you get BIG on Instagram?”

Fact is, there are many things you can do to get big on Instagram. In other words, there are lots of independent variables one can change and manipulate to test. Also, there are many things we can measure to determine if you’re big on Instagram or not. In other words, there are lots of dependent variables to measure to determine how “big” the account is getting.In this case, we’re asking for a variety of independent variables to test. However, instead of asking for a variety of dependent variables, we focus on one. Ultimately, this produces different independent variables one can test. The two examples below display the variety of answers one can get just by changing the dependent variable we are measuring.

or

This is one of our favorite examples. For one thing, it’s relevant and fun. Students already use social media, and growing a social media presence will likely resonate with some students. Also, it’s a question that has multiple answers even though there is only one outcome we are looking for. Thus, students will come up with a lot of ideas. Hopefully, those ideas will lead to a lot of discussion. And, it is through the resulting discussion that more learning will occur.

Therefore, inquiry questions lead to greater discussion. On the other hand, typical questions tend to have students just checking whether they got the “right answer”.  Why not use open ended examples for independent and dependent variable practice?

Some more fun, variables practice examples

Here are some examples we thought would be fun to have students examine and discuss. Hopefully, your students will come up with a variety of great ideas – the quirkier the better!

1. How do you make a nutritious candy bar?
2. How do you create an awesome coffee shop?
3. How do you make more friends?
4. How do you improve student wellness at school?
5. How do you make the next big music album?
6. How do you make a Youtube video go viral?
7. How do you make a city “greener”?

Remember to set either the independent or dependent variables for the students as a creative constraint. Our worksheets that are available for download have variables set already.

Have fun!

Wrap Up

Knowing how to identify independent and dependent variables in a science experiment is an important skill for students to learn. Independent  and dependent variables practice is equally as important too. And, using inquiry questions for variables practice to generate a multitude of ideas and engaging discussions is the way to go. Click the link below to download our handouts that include our images as well as our fun examples in a class ready worksheet.

Until next time, keep it REAL.

Resources

Handout(s): 26 – Variables Practice Worksheet

Our resources are free. We aren’t collecting emails for our resources. However, it would help us out if you liked us on our Facebook page and subscribed to our Youtube Channel. Thanks!

Without being able to Identify and/or distinguish variables, how can students have a proper discussion of experimental design or error when it comes to lab results? How can we expect students to design their own labs without first knowing what variables in an experiment to measure or to manipulate?

In this resource, we give a quick crash course on independent and dependent variables through the fun analogy of making a great movie. Our cheat sheet will be available for download at the end.

What is an Independent & Dependent variable?

An independent variable is the condition or factor a scientist changes during the experiment.

A dependent variable is the condition or factor a scientist measures in order to study the effects of the changes made to the independent variable.

Both independent and dependent variables are conditions the scientist measures and conditions in an experiment that change. But, independent variables are usually set or altered by the researcher to test an idea while dependent variables are measured during or after the experiment. In other words, a researcher can control or preset independent variables, while a researcher cannot preset a dependent variable.

Variables and How to Make a Great Movie

Imagine you’re a movie producer looking to make the next hugely successful movie. There are two questions you want to consider. First, what conditions help make movies become successful? And, secondly, how can we tell if a movie is successful or not?

Let’s consider the first question: What conditions help make a movie be successful? There are many potential answers for this. Perhaps, spending more money on producing the movie will help make the movie successful. Or, maybe hiring a lot of Oscar winning actors will make a movie successful. Maybe, having more visual effects will make a movie successful. There are many answers to the question, and many conditions we can test to get an answer. These conditions, which we can alter and test – conditions like money spent or actors hired – are examples of independent variables. Note that all the examples above are conditions that a movie producer can preset or control in the making of their movie.

Now, let’s consider the second question: How can we tell if a movie is great or not? Again, there are many things we can measure to find the answer.Perhaps, we can measure the amount of tickets sold to determine the success of a movie. Or, maybe, we can measure how many awards a movie wins to rate a movies success. Or, we can also use audience and critics’ reviews on RottenTomatoes.com for our measure. Again, there are many things we can measure, and many ways to answer the question. The takeaway is that the dependent variable in an experiment is what we measure (whether it be awards won or tickets sold) to determine the effectiveness of the changes done to the experiment (whether it be spending more money or using more visual effects). Also, take note that all the examples in this paragraph are conditions that a movie producer cannot preset or control. Movie producers cannot predetermine how much money they will make or how many awards they will win for a movie.

Wrap Up

The concept of the independent and the dependent variable is central to experimental design. Therefore, it’s important to have students understand the concept early in their science career. Also, it helps to have fun, relevant examples to learn from (like making movies) and practice with too. The latter is something we’ll be providing in the next post. Click the link below to download a copy of our cheat sheet for this crash course on independent and dependent variables.

Until next time, keep it REAL.

Resources

Handout(s): 25 – Variables Cheat Sheet

Our resources are free. We aren’t collecting emails for our resources. However, it would help us out if you liked us on our Facebook page and subscribed to our Youtube Channel. Thanks!

Too often, we associate “doing” science as just doing the the scientific method. More specifically, when we teach scientific method, we tend to focus on controlling and changing variables. It’s not. Science is also about analyzing and drawing inferences from data to come up with a conclusion. It’s about coming up with an explanation for what is going on – both seen and unseen. So, while making paper airplanes and adjusting their designs over and over may be a good way to quickly teach students to draw conclusions from something they can see, it does little to teach students about explaining the unseen.

A New Lesson from Old Technology (the film canister)

Using film canisters, I redesigned the classic Mystery Box Lesson to teach students to develop models to explain invisible phenomena. I use this when I teach scientific method. At the end of the post, you can sign up to get a copy of the handout I give to students emailed to you.

When I was going through the teacher education program at the University of British Columbia, I remember an activity where we were expected to develop a model for what was happening inside a black mystery box. The instructor would pour a clear, colourless solution (water, we thought) into an opening at the top of the box. A coloured solution would then exit an opening on the bottom of the box. Sometimes the solution was green or red or blue or violet. The colours changed each time more colourless solution was poured through the top. I never did find out what was happening inside the box (and to this day, I can only guess that acid-base indicators were at play). But, when I started teaching my own class, I wanted to reproduce the same experience for my students. That’s when I stumbled upon some black film canisters in our lab.

Set up & Notes from the field

Film canisters are awesome in so many ways: they’re durable, reusable, cheap (they can be free if people haven’t gotten rid of them already) or cheap to acquire, and they can be sealed. I opened a black film canister and filled it with a thumbtack, penny, and a cotton ball. I put the cap back on the film canister and wrapped the top with tape. This sealed, black film canister is my students’ mystery box.

My students need to determine what is inside the contents of their mystery box. They’re allowed to shake and play with the mystery box anyways they see fit. They drop it from different heights, roll it at different speeds. Anything (so long as they don’t destroy the mystery box or open it up). And, they end up finding different ways to interact with their mystery boxes to create different sounds. I provide students with empty film canisters and a variety of small materials – macaroni, staples, thumbtacks, cotton balls, pennies, marbles, etc – and I have them create an identical model (ie. replica) of their mystery box. It’s a lot of fun, and the students are certainly engaged with and excited about the challenge.

After 20 minutes of experimentation, we debrief the activity. We go over what they claim to be in the mystery box and what evidence supports their claim. After some discussion, we open the mystery box. This is generally followed up by a whole bunch of “I knew it”s.

Some useful tips

If you plan on doing this activity, consider the following:

• Use opaque film canisters.
• don’t fill the film canisters to the brim. Things have to be able to move in the mystery box or else it will be too challenging for the students.
• have students write down why they believe a certain piece is inside the mystery box. When asked why a student believes a penny is inside the mystery box, they might say “because it sounds like a penny.” Follow up by asking, “what exactly does a penny sound like and how did you come up with that conclusion?”
• I usually tell students that there are at least 3 items in the mystery box.
• this would be nice activity to use CER (Claim, Evidence, and Reasoning).
• as an extension, you can ask students what else can be done to determine what is inside the mystery box besides shaking the box. Students will say x-rays, but have students explore other methods. For example, some students propose weighing every piece separate and then putting different combinations of pieces together before they get the same mass as the mystery box.

Putting it all together

Making models to explain a phenomena is an important science skill. It’s also necessary to address it when we teach scientific method. And, there are better ways of doing it besides making models of the solar system or eukaryotic cell. Using film canisters to create mystery boxes is our cheap, easily accessible and highly engaging solution. If you’re interested in getting a copy of our step-by-step student handouts, click on the link below.

Until next time, keep it (ie. science) REAL.

Resources

Handout: 02 – Film Canister Mystery

Our resources are free. We aren’t collecting emails for our resources. However, it would help us out if you liked us on our Facebook page and subscribed to our Youtube Channel. Thanks!